12. Subjects who regularly use prescription medications unrelated to the complications of obesity (especially vasoactive compounds such as calcium channel blockers, nitrates, beta-blockers, etc.), subjects using H2 blockers for dyspepsia, and subjects who require chronic use of antihistamines for allergic conditions; oral contraceptive use will be permitted, provided the contraceptive has been used for at least two months before starting study medication. The use of over-the-counter and prescription medications will be reviewed on a case-by-case basis; depending on the medication, subjects who have continued to take prescription medication for at least 3 months prior to study entry may be eligible. Allowable medications may include statins for the treatment of dyslipidemia and low-dose aspirin for primary prevention of acute coronary syndrome. Medications used for the treatment of hypertension will not be allowed because of the potential vasodilatory activity of betahistine.